1) Field of the Invention
The present invention relates to a slat conveyor, and more particularly to a slat conveyor used to deliver or classify articles or baggage in an airport, delivery center, etc.
2) Description of Related Art
Traditionally, a slat conveyor, which can be used regardless of the type of articles to be conveyed, has been used in several fields. The slat conveyor has several kinds of formats.
An example of the slat conveyor will be explained below. In many cases, as shown in FIG. 5, in order to convey an article to a predetermined position, frames 40 are fixed on a floor by an anchor bolt to form a conveying path 41 having a path bent as necessity requires. An endless chain 42 is mounted on the center line of the conveying path 41. On the chain 42, a large number of slat supporting members 43 as shown in FIG. 6 (A--A section in FIG. 5) are attached, and on the slat supporting members 43, square slats 44 made of synthetic rubber are attached.
The above chain 42 is formed endlessly and rotatably in such a manner that a set of chain links 45 arranged on right and left sides (face and back of the drawing) and a set of chain links 46 arranged on the upper and lower sides are alternately combined. Cross-shape shafts 47 are arranged at points where the chain links 45 and the chain links 46 are connected. A roller 48 is rotatably provided on the axis of each of the shafts 47 extended vertically, and is adapted to roll along a guide (not shown) provided at the position where the chain 42 is mounted on the center portion of the frames 40.
A roller 49 is also rotatably provided on the axis of each of the shafts 47 (face and back sides of the drawing), and is adapted to rotate along the guide (not shown) provided on the frames 40. The chain 42 is moved along the conveying path 41 by a driving device (not shown). The slat supporting member 43 is attached to each chain link through a bolt member 50. The slats 44 attached on the slat supporting members 43 are configured so that on the lower side of tail end of a certain slat, the upper surface of the front end of a succeeding slat is superposed in a direction of the travelling direction of the slat supporting members 43 so that the article placed on the slat 44 can be smoothly conveyed without dropping the article from the conveying path 41.
However, the conventional slat conveyor having the above arrangement has the following problem. The use for a long time gives rise to extension or stretch of the chain owing to the wear of the shafts connecting the chain links. This leads to the inconvenience such as backlash in the chain links so that smoothness in the travel at the curve of the conveying portion is lost to generate vibration and noise.
For this reason, in order to obviate the above inconvenience, in the prior art, the travelling system inclusive of the frames, travelling rails, etc. must be shifted in accordance with extension of the chain. For example, as indicated by double-dotted chain lines in FIG. 5, the travelling system was adjusted at the portions of connecting the curve portion and straight portion of the frames of the conveyor. Specifically, the curve portions were shifted and the gaps thus generated were filled with some new member. However, since the frames are usually fixed to a floor by anchor bolts, such an adjusting method has a problem that much labor and time as well as large-scale construction are required. Further, in order to exchange worn shafts, all of many shafts must be checked and the chain must be dismantled and reassembled, thus requiring much labor and time.